Gas-operated automatic firearm



Aug. 13, 1940. J. E. BRowNlNG 2,211,405

GAS-OPERATED AUTOMATIC FIREARM Original Filed Aug. 31, 1938 Patented Aug. 13, 1940 UNETED STATES 2,211,405 GAS-OPERATED AUTOMATIC FIREARM Jonathan E. Browning, Ogden,

Utah, assigner, by

mesne assignments, to Western Cartridge Company, a corporation of Delaware Application August 31, 1938, Serial No. 227,712 Renewed December 11, 1939 10 Claims.

This invention relates to an improvement in automatic firearm, and more particularly to that class of automatic firearms which are operated for e'ecting the ejection of a red cartridge and .for reloading, by gas pressure acting upon a tubular piston and developed by the ring of a cartridge.

One of the objects of the present invention is to provide a superior iirearm of the type referred to. in which provision is made for avoiding the cramping or binding of the tubular piston despite strains placed thereon as the result of its operative connection to the action of the firearm.

Another object is to provide a superior gasoperated automatic firearm having a tubular piston and in which expansion and contraction incident to the development of heat occasioned by the firing of the rearm will not cause the binding of the said tubular piston.

A further object is toprovide a superior automatic rearm of the type referred to, in which a tubular piston is operatively connected to the action of the rearm by means of an actionslide or its equivalent which reciprocates obliquely with respect to the normal path of movement of the said tubular piston, and in which simple, reliable and eii'ective means is provided for avoiding the cramping of the parts despite the divergence between the respective paths of movement of the said tubular piston and the said actionslide.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawing, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a broken view partly in side elevation and partly in vertical central-longitudinal section of one form which a gas-operated automatic firearm embodying the present invention may assume;

Fig. 2 is a fragmentary view partly in side elevation and partly in vertical central-longitudinal section of the portion of the firearm immediately adjacent to the piston and cylinder;

Fig. 3 is a view corresponding to Fig. 2 but showing the tubular-piston moved rearwardly under the urge of gas pressure to effect the actuation of the rearm;

Fig. 4 is a transverse sectional view taken on the line 4 4 of Fig. 2;

portion I8 and the internal diameter of Fig. 5 is a transverse sectional view taken on the line 5-5 of Fig. 3; Fig. 6 is a perspective view of the tubular-piston together with a portion of the actuating-rod; and

Fig. 7 is a broken view portion of the barrel.

The particular gas-operated automatic rearm herein chosen for the illustration of the present invention includes a receiver I from which forl0 wardly projects a barrel II rigid with respect to the said receiver and provided with the usual axial passage or bore i 2 through which the projectile and accompanying burning or burnt gases may pass forwardly. Attached to the barrel II l and to the receiver I0 is a stock i3, the forward 6 in side elevation of a portion of which is provided with a recess I@ into which projects the lower portion of a stockattaching lug I5 depending from the barrel I I. Mounted in the underface of the stock i3 in 2o alignment with the stock-attaching lug i5 is an escutcheon I6 through which extends a vertical screw I7 threaded into the said stock-attaching lug i5.

Adjacent its forward end the barrel il is formed with a smooth cylindrically-contoured portion I8 which is larger in diameter than the portion of the barrel immediately to the rear thereof and which for convenience of description may be referred to as a piston-core or piston-guiding portion. Also for purposes of convenience of description, the portion I9 of the barrel II which lies immediately to the rear of the piston-guiding portion I8 just referred to, will be termed or referred to as a piston-releasing portion, since it is of a diameter very materially smaller than the diameter of the piston-guiding a tubular-piston to be presently described.

Sliding axially along the piston-g'uiding por- 40 tion I8 around which it is normally located, is

a tubular-piston 20 having an internal diameter suiliciently larger than the external diameter of the piston-guiding portion of the barrel Ii so as to freely reciprocate thereon without occasioning harmful binding or cramping or undue gas-leakage. A clearance of approximately ten thousandths of an inch between the piston-guiding portion I8 and the inner surface of the tubular-piston 20 has been found to be satisfactory. 50

Extending rearwardly from the tubular-piston 20 above referred to in rigid relationship thereto is an actuating-rod ZI preferably extending rearwardly beneath the barrel II through a clearance-groove 22 in the forward portion of 55 the stock I8, and intova relatively deep longitudinally-extendlng pocket 23 'also formed in the stock I8. At its rear end the actuating-rod is formed with a laterally flattened head 24 which is pivotally connected by means of a stud 25 to the forward end of an action-slide 26 which reciprocates in an oblique path with respect to the axis of the barrel II, as is clearly indicated in Fig. 1.

The action-slide 26 above referred to, has pivotally connected to its rear end the lower end of a bolt-operating link 21 which in turn has its upper end pivotally coupled to the rear end of a breech-bolt 28 (Fig. l). Extending rearwardly from the rear end of the action-slide 26isaspringplunger 28 encircled by a breech-bolt-closing spring 38 serving to restore the breech-bolt 28 to its forward or closed position as shown in Fig. 1, after the said breech-bolt has been thrown rearwardly by gas pressure impinging upon the forward edge of the tubular-piston 28, in a manner as will hereinafter appear.

As is usual in automatic firearms, the rearward movement of the breech-bolt 28 eilects the extraction and ejection of a fired cartridge. Upon its forward travel under the urge of the breech-bolt-closing spring 38, the breech-bolt 28 acts to insert a fresh cartridge into the firing chamber of the arm preparatory to another cycle of operation under the control of a trigger 3l. The said trigger 3I is located lwithin a triggerguard 32 which forms a rigid feature of a triggerplate 33 secured in any suitable manner to the under side of the-receiver I8, all as more fully set forth in detail in my copending application Serial No, 136,523 filed April 13, 1937.

For the purpose of enabling a user of the ilrearm to manually retract the breech-bolt 28 an L- shaped link 34 (Fig. 1) is employed. The link 34 just referred to, comprises a 'relatively-long substantially-horizontal arm 35 from the forward end of which downwardly extends a substantially-vertical and relativelyL-short arm 36. The substantially-vertical arm 36 of the link 34 is operatively coupled to the forward portion of the action-slide 26 by means of a stud 31 and the rear end of its complemental arm 35 is guided for reciprocating movement in a guide-groove 38 formed in the side wall of the receiver I8. The rear end of the horizontal arm 35 of the link 34 is provided with an operating-handle 38, as shown in Fig. 1.

Adjacent its rear end the action-slide 26 has pivotally connected to it the lower end of the breech-bolt-operating link 21 which has its upper end pivotally connected to the lower rear portion of the breech-bolt 28 as before referred to. Through the intermediary of the link 21 the action-slide 26, upon its rearward travel, effects the rearward retraction of the said breech-bolt 28 and conversely on its forward movement the said action-slide effects the advance of the breech-bolt 28 into its breech-closing position and the locking thereof in the latter position.

Extending rearwardly over the piston-guiding portion I8 of the barrel II in radially spaced relationship with respect thereto, is the skirt 48 having approximately ten thousandths of an inch clearance with respect to the outer surface of the piston 28 of a'cylinder generally designated by the reference character 4I. The said cylinder also has an internally-threaded forward portion 42 threaded onto an externally-threaded portion 43 formed on the barrel I I immediately forwardly of the piston-guiding portion I8 thereof. As thus mounted upon the barrel II the cylinder 4I is adapted to be adjusted to positions either slightly rearwardly or slightly forwardly of the position in which it is shown in Figs. l, 2 and 3, in order to further close off or further open up more of the cross-sectional area of a gas-port 44 extending radially through the wall of the barrel il from the interior bore I2 .thereof to the exterior surface ofthe piston-guiding portion I8 of the said barrel. In registry with the outer terminus of the gas-port 44 is a notch 46 formed in the rear edge of the tubular-piston 28.

As the parts above described are constructed and arranged, there is provided a tubular gaschamber 46 between the periphery of the pistonguiding portion I8 of the barrel Il and the interior surface of the skirt 48 of the cylinder 4I.

Normally located in the tubular gas-chamber 46 just above referred to, is the tubular-piston 28 which is adapted to be forced rearwardly for the operation of the firearm, by means of a gas escaping from the bore I2 radially outwardly through the gas-port 44 into the forward end of the said gas-chamber 46 in registration with the notch in the forward edge of the tubularpiston 28.

The rear portion of the outer periphery of the skirt 48 of the cylinder 4I, is provided with an annular groove 41 in which is seated the forward end of a tubular-guard 48 preferably formed of light sheet metal and having its rear end seated against the forward end of the stock I3. The said tubular-guard 48 is so sized and shaped as to provide clearance for the rearward travel of the tubular-piston 28 and for the movement of the actuating-rod 2i.

For brevity of description it may be stated that 4the breech-bolt 28 and associated parts which are actuated by the action-slide 26 are to be considered as` constituting the so-called action of the firearm illustrated, in accordance with well understood terminology in the art.

For the purpose of making clear the operation of the firearm herein chosen for illustration, let it be assumed that the tubular-piston 28 is occupying the position in which it is shown in Figs. 1 and 2 of the accompanying drawing, under the urge of the breech-bolt-closing spring 38.

Now when the trigger 3| is operated in the usual manner of firearms, a cartridge will be discharged with the result that the projectile will be propelled forwardly through the bore I2 of the barrel II under the force of the burning powder charge. As the projectile passes beyond the inner end of the gas-port 44 the gas under pressure back of the said projectile, will escape radially outwardly through the said gas-port 44 into the tubular gas-chamber 46 to thereby kick so to speak, the tubular-piston 28 rearwardly with the result that the actuating-rod 2l, the actionslide 26, the breech-bolt 28 and associated parts will all be moved rearwardly against the tension of the spring 38. In this manner the casing of the fired cartridge will be' ejected and the firing mechanism will be cocked preparatory to the return movement of the breech-block 28, actionslide 26 and associated parts to their former positions as illustrated in Figs. 1 and 2.

As is usual in automatic firearms, when the breech-bolt 28 moves forwardly after having been retired in the manner above described the said breech-bolt will insert a fresh cartridge into the cartridge chamber in the rear end of the barrel I I, preparatory to again firing the gun by means of the actuation of the trigger 3l.

aai nace As the tubular-piston 2G moves rearwardly when the rearm is discharged. the said piston will pass rearwardly off from the piston-guiding portion i8 of the barrel il and beyond the rear edge of the skirt at of the cylinder d5. During its rearward movement as just above described, the tubular-piston 2li will assume substantially the position in which it is shown in Fig. 3 in which it will be noted that the axis of the said tubular-piston and the barrel H now have an angular relationship due to the downward travel of the rear end of the actuating-rod 2l caused by its attachment to the forward end of the action-slide, 26. Since the actuating-rod 2i is rigid with the tubular-piston 2@ it follows that the piston 2d will be canted as it travels rearwardly. Owing however to the fact that the piston 2li rides oi from the piston-guiding portion i3 of the barrel IS shortly after its rearward movement is initiated the cramping of the said piston upon the piston-guiding portion i3 is avoided.

When the tubular piston 2Q moves forwardly from theA position in which it is shown in Fig. 3 to the position in which it is shown in Figs. 1 and 2, the tapering-junction 9 between the piston-releasing portion i9 and the rear end of the piston-guiding portion i 8 will serve to insure that the said piston is guided concentrically into the tubular gas-chamber d preparatory to another cycle oi operation.

In the general manner above described the tubular-piston 28 or its equivalent is prevented from harmfully binding upon the barrel by permitting the said piston to move rearwardly over a portion of the barrel having very materially smaller diameter than the interior diameter of the said piston, thus enabling a, very simple,

reliable and effective construction and arrangement of parts to be employed.

The invention may be carried out in other specc ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and

all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. A gas-operated automatic firearm, including in combination: a firearm-action; a tubularpiston operatively-connected to the said rearinaction; a barrel extending through the hollow interior of the said tubular-piston and having a relatively-large-diameter piston-guiding portion relatively-snugly tting the interior of the said tubular-piston, and the said barrel also having a relatively-small-diaxneter piston-releasing portion adjacent to the said piston-guiding portion and tting the interior of the said tubular-piston to a degree freely permitting the appreciable tilting or canting thereof with respect to the axis of the said barrel; and means for applying gas pressure from the interior of the said barrel to the said tubular-piston for moving the same on" from the piston-guiding portion of the said barrel and onto the piston-releasing portion thereof and in adirection required to operate the said rearm-action; whereby the said tubular-piston upon being moved over the piston-releasing portion of the said barrel is freed for tilting movement with respect to the arn's of the said barrel to thus guard against the cramping of the said tubular-piston upon the said barrel.

2. A gas-operated automatic rearm, including in combination: a firearm-action; a tubularpiston operatively-connected to the said firearmaction; a barrel extending through the hollow interior of the said tubular-piston and having a relatively-large-diameter piston-guiding portion relatively-snugly fitting the interior of the said tubular-piston, and the said barrel also having a relatively-small-diameter piston-releasing portion located immediately to the rear of the said piston-guiding portion and freely fitting the interlor of the said tubular-piston to a degree freely permitting the appreciable tilting or canting thereof with respect to the axis of the said barrel; and means for applying gas pressure from the interior of the said barrel to the forward edge of the said tubular-piston for moving the same rearwardly on from the piston-guiding portion of the said barrel and onto the piston-releasing portion thereoi7 to effect the operation of the said firearm-action; whereby the said tubular-piston upon being moved rearwardly over the pistonreleasing portion of the said barrel is freed for tilting movement with respect to the axis of the said barrel to thus guard against the cramping of the said tubular-piston upon the said barrel.

3. A gas-operated automatic firearm, including in combination: a. firearm-action; a tubularpiston; a barrel extending through the hollow interior of the said tubular-piston and having a relatively-large-diarneter piston-guiding portion relatively-snugly fitting the interior of the said tubular-piston, and the said barrel also having a relatively-small-diameter piston-releasing portion adjacent to the said piston-guiding portion and fitting the interior of the said tubular-piston to a. degree freely permitting the appreciable tilting or canting thereof with respect to the axis of the said barrel; an actuating-rod operatively connected to the said tubular-piston` for being moved thereby and also operatively connected to the said firearm-action; and means for applying gas-pressure from the interior of the said barrel to the said tubular-piston for moving the same off from the piston-guiding portion of the said barrel and onto the piston-releasing portion thereof and in a, direction required to cause the said actuating-rod to operate the said rearm-action.

a. A gas-operated automatic firearm, including in combination: a firearm-action; a tubularpiston; a barrel extending through the hollow interior of the said tubular-piston and having a relatively-large-diameter piston-guiding portion relatively-snugly fitting the interior of the said tubular-piston, and the said barrel also having a relatively-small-diameter piston-releasing portion located immediately to the rear of the said piston-guiding portion and tting the interior of the said tubular-piston to a degree freely permitting the appreciable tilting or canting thereof with respect to the axis of the said barrel; an

actuating-rod operatively connected to the said tubular-piston and extending rearwardly therefrom and operatively connected to the said firearm-action; and means for applying gas-pressure from the interior of the said barrel to the forward edge of the said tubular-piston for moving the same rearwardly off from the pistonguiding portion of the said barrel and onto the piston-releasing portion thereof.

5. A gas-operated automatic firearm, including in combination: a firearm-action; a tubularpiston; a barrel extending through the hollow interior of the said tubular-piston and having a relatively-large-diameter piston-guiding portion relatively-snugly iltting the interior of the said tubular-piston, and the said barrel also having a relatively-small-diameter piston-releasing portion adjacent to the said piston-guiding portion and iltting the interior of the said tubular-piston to a degree freely permitting the appreciable tilting of canting thereof with respect to the axis of the said barrel; an actuating-rod rigidly connected to the said tubular-piston and operatively connected to the said firearm-action; and means for applying gas pressure from the interior of the said barrel to the said tubularpiston for moving the same of! on the pistonguiding portion of the said barrel and onto the piston-releasing portion thereof and in a direction required to cause the said actuating-rod to operate the said firearm-action 6. A gas-operated automatic ilrearm, including in combination: a firearm-action; a tubularpis/ton; a barrel extending through the hollow interior of the said tubular-piston and having a relatively-large-diameter piston-guiding portion relatively-snugly fitting the interior of the said tubular-piston, and the said barrel also havv ing a relatively-small-diameter piston-releasing portion located immediately to the rear of the said piston-guiding portion and iitting the interior of the said tubular-piston to a degreeefreely permitting the appreciable tilting or canting thereof with respect to the axis of the said barrel; an actuating-rod rigidly connected to the said tubular-piston and extending rearwardly therefrom into operative connection with the said firearm-action; and means for applying gas pressure from the interior of the said barrel to theforward edge of the said tubular-piston for moving the same rearwardly off from the pistonguiding'portion of the said barrel and onto the piston-releasing portion thereon to effect the operation on the said firearm-action.

7. A gas-operated automatic firearm, including in combination: a firearm-action; a barrel provided upon its exterior with a piston-guiding portion adapted to relatively-snugly fit the interior of' a ,tubular-piston, the said l'Darrel also being provided with a piston-releasing portion located adjacent the said piston-guiding portion and of appreciably-lesser diameter than the same; a tubular-piston normally surrounding the piston-guiding portion of the said barrel and movable axially toward the said piston-releasing portion thereof; and means for applying gas pressure from the said barrel to one end of the said tubular-piston for moving the same axially of the said barrel from the piston-guiding portion thereof to the piston-releasing portion thereof to thereby permit the said tubular-piston to tilt.

with respect to the axis of the piston-guiding portion of the said barrel as the said tubularpiston moves axially under the impulse of gas Y f pressure from the said barrel to effect the operation of the said firearm-action.

8. A gas-operated automatic firearm, including in combination: a barrel provided upon its exterior with a piston-guiding portion adapted to relatively-snugly flt the interior of a tubularpiston, the said barrel also being provided with a piston-releasing portion located immediately adjacent the said piston-guiding portion and of appreciably-lesser diameter than the same; a breech-bolt; an action-slide mounted for reciprocation in an oblique path with respect to the axis of the said barrel and operatively connected to the said breech-bolt; a tubular-piston normally surrounding the piston-guiding portion o! the said barrel and movable axially toward the said piston-releasing portion thereof and operatively connected to the said action-slide; and means for applying gas-pressure from the said barrel to one end of the said tubular-piston for moving the same axially with respect to the said barrel from the said piston-guiding portion thereof onto the piston-releasing portion thereof, to thereby permit the said tubular-piston to tilt with respect to the axis of the piston-guiding portion of the vsaid barrel as the said tubularpiston moves axially under the impulse of gaspressure from the said barrel to eflect the operation of the said action-slide and breech-bolt.

9. A gas-operated automatic firearm, including in combination: a barrel provided upon its exterior with a piston-guiding portion adapted to relatively-snugly t the interior of a tubularpiston, the said barrelalso being provided with a piston-releasing portion located immediately adjacent the said piston-guiding portion and of appreciably-lesser diameter than the same; a breech-bolt; an action-slide mounted for reciprocation in an oblique path with respect to the axis of the said barrel and operatively-connected to the said breech-bolt; a tubular-piston normally surrounding the piston-guiding portion of the said barrel and movable axially onto the said piston-releasing portions thereof; an actuatingrod operatively-interposed between the said tubular-piston and the said action-slide; and means for applying gas-pressure from the said barrel to one end of the said tubular piston for moving the same axially with respect to the said barrel from the said piston-guiding portion thereof onto the piston-releasing portion thereof as the said tubular piston moves axially under the impulse of gas-pressure from the said barrel to effect the operation of the said actuating-rod. action-slide and breech-bolt.

10. A gas-operated automatic rearm, including in combination: a barrel provided upon its exterior with a piston-guiding portion adapted to relatively-snugly fit the interior of a tubularpiston, the said barrel also being provided with a piston-releasingportion located immediately to the rear of the said piston-guiding portion and of appreciably-lesser diameter than the same; a breech-bolt; an action-slide mounted for reciprocation in an oblique path with respect' to the axis of the said barrel and operatively-connected to the said breech-bolt; a tubular-piston normally surrounding the piston-guiding portion of the said barrel and movable axially onto the said piston-releasing portions thereof; an actuating-rod rigidly connected at its forward end to the said tubular-piston and operatively connected adjacent its rear end to the said actionslide; and means for applying gas-pressure from the said barrel to the forward end oi?v the said tubular-piston for moving the same axially with respect to the said barrel from the said pistonguiding portion thereof onto the piston-releasing portion thereof as the said tubular-piston moves axially under the impulse of gas-pressure from the said barrel to eiect the operation of the said actuatingrod, action-slide and breech-bolt.

JONATHAN E. BROWNING. 

